The following is a summary of “COVID-19 booster dose induces robust antibody response in pregnant, lactating, and nonpregnant women,” published in the January 2023 issue of Obstetrics and Gynecology by Atyeo, et al.

The use of booster doses of the messenger RNA vaccine was motivated by the rapid waning of vaccine-induced immunity and the appearance of concerning variants, despite emerging data from the SARS-CoV-2 pandemic showing robust messenger RNA vaccine-induced immunogenicity across populations, including pregnant and lactating women. It was unknown if all populations, including those who were pregnant or nursing, would respond similarly to a booster dosage. For a study, researchers sought to characterize the humoral immune response to a booster dose of COVID-19 messenger RNA in a cohort of pregnant, lactating, and nonpregnant women who were age-matched.

In a cohort of 31 pregnant, 12 lactating, and 20 nonpregnant age-matched individuals who received a BNT162b2 or messenger RNA-1273 booster dose following initial COVID-19 immunization, the study assessed the antibody response against ancestral Spike and Omicron. They also looked at 15 maternal-to-cord dyads’ vaccine-induced antibody levels at delivery.

Immunoglobulin G1 levels against Omicron Spike rose after receiving a booster dose during pregnancy (postprimary immunization vs. post booster dose; P=.03). Compared to non-pregnant women, pregnant and breastfeeding people showed equal levels of total immunoglobulin G1, immunoglobulin M, and immunoglobulin A, as well as neutralizing titers against Omicron. The immunological response to a booster dosage in pregnant vs. nonpregnant people showed subtle variations in Fc receptor binding and antibody subclass profiles. In comparison to maternal blood (P=.002), the cord blood had larger levels of spike-specific FcR3a-binding antibodies, which was consistent with the preferred transfer of highly functional immunoglobulin, according to the study of maternal and cord antibody profiles after delivery. In addition, the amount of time that had passed after receiving the booster dosage was positively linked with the levels of spike-specific immunoglobulin G1 in the cord (Spearman R,.574; P=.035).

According to the study’s findings, obtaining a booster dosage while pregnant caused a strong humoral immune response unique to Spike, including protection from Omicron. Higher Spike-specific cord immunoglobulin G1 levels were attained with more time passing between getting the booster and delivery if boosting takes place in the third trimester of pregnancy. It may enhance maternal and neonatal immunity to get a booster dosage.

Reference: ajog.org/article/S0002-9378(22)00562-2/fulltext